Observation of the spin-charge thermal isolation of ferromagnetic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ga</mml:mi></mml:mrow><mml:mrow><mml:mn>0.94</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Mn</mml:mi></mml:mrow><mml:mrow><mml:mn>0.06</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">As</mml:mi></mml:math>by time-resolved magneto-optica

Kojima, Eiji; Shimano, Ryo; Hashimoto, Y.; Katsumoto, Shingo; Iye, Yasuhiro; Kuwata‐Gonokami, Makoto

doi:10.1103/physrevb.68.193203

Cited by 65 publications

(67 citation statements)

References 26 publications

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“…A different process with a similar relaxation time ∼ 1ps has been observed previously, and has been attributed to trapping of photoexcited electrons by crystal defects, with no relation to the magnetic system [38][39][40] . Our present results thus point to a need for future studies aimed at a better understanding of the hole-energy dynamics occurring in ferromagnetic semiconductors.…”

Section: A Short-time Dynamics: Hole Spin and Energy Relaxationmentioning

confidence: 75%

Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Patz

Liu

et al. 2015

Phys. Rev. B

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We report direct measurements of hole spin lifetimes in ferromagnetic GaMnAs carried out by time-and polarization-resolved spectroscopy. Below the Curie temperature, ultrafast photoexcitation of GaMnAs with linearly-polarized light is shown to create a non-equilibrium hole spin population via dynamical polarization of the holes through p-d exchange scattering with ferromagneticallyordered Mn spins. The system is then observed to relax in a distinct three-step recovery process: (i) a femtosecond hole-spin relaxation, on the scale of 160-200 fs, (ii) a picosecond hole-energy relaxation, on the scale of 1-2 ps, and (iii) a coherent, damped Mn spin precession with a period of 250 ps. The transient amplitude of the hole-spin relaxation component diminishes with increasing temperature, directly following the ferromagnetic order of GaMnAs, while the hole-energy amplitude shows negligible temperature change. Our results serve to establish the hole spin lifetimes in the ferromagnetic semiconductor GaMnAs, at the same time demonstrating a novel spectroscopic method for studying non-equilibrium hole spins in the presence of magnetic order and spin exchange interaction.

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Section: A Short-time Dynamics: Hole Spin and Energy Relaxationmentioning

confidence: 75%

Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Patz

Liu

et al. 2015

Phys. Rev. B

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“…(2) in [17]). The former reflects the pump-induced change of the sample magnetization and the latter is connected with the pump-induced change of the electronic properties of the sample [17]. Recently, we have showed that the oscillatory part of the signal is very similar in the Kerr rotation and ellipticity measurements (see Fig.…”

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confidence: 99%

Coherent control of magnetization precession in ferromagnetic semiconductor (Ga,Mn)As

Rozkotová

Němec

Tesařová

et al. 2008

Applied Physics Letters

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We report single-color, time resolved magneto-optical measurements in ferromagnetic semiconductor (Ga,Mn)As. We demonstrate coherent optical control of the magnetization precession by applying two successive ultrashort laser pulses. The magnetic field and temperature dependent experiments reveal the collective Mnmoment nature of the oscillatory part of the time-dependent Kerr rotation, as well as contributions to the magneto-optical signal that are not connected with the magnetization dynamics.The lasting demand for increased speed of writing and retrieving magnetically stored information in computer hard drives stimulated an intense research of ultrafast magnetization dynamics. In particular, the ultrafast control of magnetization by laser pulses has gained a significant attention recently [1]. Initially, the research was focused mainly on ferromagnetic metals and half-metals where the impact of ultrashort (subpicosecond) laser pulses can lead to demagnetization [2], magnetization rotation [3] or even to modification of magnetic structure [4]. More recently, also the investigation of diluted magnetic semiconductors (DMSs) has started. The most intensively studied example of DMSs is (Ga,Mn)As where the ferromagnetic coupling between Mn local-moments is meadiated by spin-polarized valence band holes [5]. In the last few years, not only the ultrafast demagnetization [6] but also the ultrafast enhancement of ferromagnetism [7], the complete reversal of magnetic hysteresis loop [8] and the laser-induced precession of magnetization [9][10][11] were demonstrated in (Ga,Mn)As.Ultrashort laser pulses can be also used for coherent control of the spin precession. In this experiment the sample is excited by pairs of pump pulses. Each pump pulse generates a transient precession of magnetization vector and their temporal separation (i.e., the mutual phase difference between the corresponding magnetization precessions) determines if they superimpose constructively or destructively. Coherent control of magnetization was demonstrated in various types of magnetic materials -ferrimagnetic garnet [1], antiferromagnetic orthoferrites [1], half-metalic ferromagnetic CrO 2 [12], and paramagnetic (Cd,Mn)Te [13].In this paper, we report on the coherent control of magnetization precession in ferromagnetic (Ga,Mn)As. The experiments were performed on an annealed 50 nm thick ferromagnetic (Ga,Mn)As film with nominal Mn doping of 7% and the Curie temperature T C ≈ 160 K, which was grown by the low temperature molecular beam epitaxy (LT-MBE) on a GaAs(001) substrate. The sample exhibits in-plane easy axis behavior typical for stressed (Ga,Mn)As layers grown on GaAs substrates. The external magnetic field (generated by an a) Electronic mail: nemec@karlov.mff.cuni.cz 1

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“…© 2007 American Institute of Physics. ͓DOI: 10.1063/1.2719173͔ Current research activities in the area of ferromagnetic semiconductor have been mainly focused on III-Mn-V alloys with small lattice constants and large effective masses of valence band such as GaMnAs, [1][2][3][4] where the highest values of the Curie temperature ͑T C ͒ have been achieved so far. Various theoretical models have been proposed to explain the actual mechanism of ferromagnetism in III-Mn-V but the microscopic mechanism is still a matter of controversy.…”

mentioning

confidence: 99%

Relaxation of photoinduced spins and carriers in ferromagnetic InMnSb films

Nontapot

Kini

Gifford

et al. 2007

Applied Physics Letters

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Observation of the spin-charge thermal isolation of ferromagneticGa0.94Mn0.06Asby time-resolved magneto-optica

Cited by 65 publications

References 26 publications

Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Coherent control of magnetization precession in ferromagnetic semiconductor (Ga,Mn)As

Relaxation of photoinduced spins and carriers in ferromagnetic InMnSb films

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